The present invention relates to multiple image cameras and more particularly concerns a compact packaging of the camera and its optical system to provide a lightweight, small size package that enables multiple images of a display to be successively directed to different areas of a photographic sheet film.
In the course of certain types of medical analyses and diagnoses, electromagnetic or other types of radiated, energy, is received from a patient's body by a suitable scanning device, converted into electrical signals and fed to an oscilloscope or video monitor having a screen upon which appears a display that conveys useful medical information. Because of the momentary and ever changing nature of the display on the oscilloscope screen, it is common practice to make a permanent photographic record of the display using a standard eight inch by ten inch sheet film or equivalent. Generally, the display on the oscilloscope screen is decreased in size, electronically, optically, or both, to enable photographing, on the single sheet, an array of four, six or nine images successively appearing on the display screen. A number of different types of cameras and camera oscilloscope combinations have been developed to enable shifting of the optical image of the display screen in two directions, in X and in Y, relative to the sheet film so as to provide a suitable number of mutually spaced and precisely positioned images thereon.
One multiple image camera of this type is shown in the patent to Barney U.S. Pat. No. 4,027,316, in which a sheet film is positioned in front of and parallel to the oscilloscope display screen and an optical system is interposed between the two. The optical system carries a lens that is movable vertically and horizontally, in X and Y directions generally parallel to the plane of the display screen, so as to provide the desired pattern and number of images of the video display. As compared to a camera having a film carrier movable in both X and Y directions, the movable lens arrangement requires smaller motions of the lens and presents lesser light sealing problems. Such an arrangement, however, requires the shiftable lens be operated in an off axis mode in most positions. This is undesirable optically, providing brightness differentials and, if the video monitor has a curved screen, also providing variable distortion from one lens position to the next. Moreover, because there is a minimum length of optical path, required by commonly used lenses, between the film and the display, arrangements of the type illustrated in the Barney patent are undesirably large. The optical path length requires a longer distance between display screen and film carrier to house a lens and film in appropriate positions directly in front of the display screen. Since cameras of this type generally supplement other scanning and diagnostic equipment, size and space requirements are of major importance. Thus, a multiple image camera of the type shown by Barney requires a large table or other horizontal support, if the display screen is oriented in a vertical plane. To conserve horizontal space, the multiple image movable lens camera is often floor mounted, with the display screen oriented in a horizontal plane, but again this requires an excessive amount of vertical space.
Another type of multiple image camera used for medical purposes provides an arrangement in which the lens system is fixed to the monitor and the entire monitor and lens system are moved together in X and Y relative to a fixed film. This arrangement solves the off-axis optical problem, but is also exceedingly large and bulky. Moreover, the requirement to move the monitor, not only horizontally, but also vertically, imposes more severe requirements upon the supporting and driving structure which must raise the entire monitor and optical assembly. Again, this arrangement is undesirably large for reasons similar to those related to size of the moving lens camera.
Although the use of a mirror in an optical system for folding an optical path is known as shown, for example, in the U.S. Pat. No. 2,166,440, no cameras are known to applicant which minimize overall packaging dimensions with a multi-image format, nor which employ an optimum arrangement of folded optical path with selected motion of camera parts so as to provide a combined video monitor and camera combination of minimum size.